Method for monitoring living body activities, and optical fiber type flat shaped body sensor, garment styled optical fiber type flat shaped body sensor and human body fitted optical fiber type flat shaped body sensor used for the same

ABSTRACT

A living body monitoring activity system detects major activities, or feeble living body activities. In a method for monitoring existence of human movements or living body activities in living environments (e.g., sleeping activities involving a bed, a Futon-mat, a pad, or a Tatami-mat), an optical fiber type flat shaped body sensor including an optical fiber affixed or fitted to a flat shaped body is used, and light is emitted into the optical fiber from a light source, and changes of polarized wave conditions of light propagating in the optical fiber are brought about by changes in form of the optical fiber type flat shaped body sensor caused by human movements or living body activities and are detected by a measuring apparatus for polarized wave fluctuations so human activities or movements are discriminated based on the detected value of the polarized wave fluctuations.

TECHNICAL FIELD

The present invention is mainly utilized in the fields such as medicalcare or nursing care and the like, and relates to a method formonitoring living body activities or movements on a floor, a bed or aTatami-mat and the like which makes it possible that human bodyactivities or movements are sensed or monitored from a distanceautomatically and with high accuracy, and an optical fiber type flatshaped body sensor used for the same. More specifically, the presentinvention relates to a method for monitoring living body activitieswhich makes it possible that all human body activities and movementsincluding respiration, pulsation and the like are detected with highaccuracy under exactly the same conditions as those of ordinary livingenvironments without using a purpose-made bed, a special-made Futon-bedand the like by means of detecting fluctuations of the polarized wave oflight inside an optical fiber brought about by human activities on a bedsheet, a mat, a pad, a Tatami-mat, a floor cover, a carpet and the likeand underneath a quilt cover or a blanket by utilizing an optical fiberincorporated bed sheet, quilt, blanket, mat, pad, Tatami-mat, floorcover, carpet and the like (hereinafter called an optical fiber typeflat shaped body sensor) with the aid of a highly sensitive polarizedwave fluctuations measuring apparatus, and an optical fiber type flatshaped body sensor, a garment styled optical fiber type flat shaped bodysensor, and a human body fitted optical fiber type flat shaped bodysensor used for the same.

TECHNICAL BACKGROUND

Conventionally, in the field of medical care, nursing care and the like,a distance monitoring system for so-called nursing care and the like hasbeen developed aiming at effective nursing with less staff by means ofmovements of a patient, the cared and the like in a hospital room beingconveyed to a nurse station or a ward through a cable or cable-freesystem. Today, the development of this kind of a monitoring system isactively under way.

Among others, in recent years, a monitoring system for which an opticalfiber is employed as a monitoring sensor for living body activities hasreceived a widespread attention because of its excellent detectionsensitivity and stability, while a conventional piezoelectric sensor ora vibration type sensor used for the similar living body activities isable to detect movements such as going to bed, rising from bed ortossing and turning in bed and the like of a human accurately to someextent, but it is found difficult to detect movements of a humanincluding respiration and pulsation with high accuracy.

A monitoring system for living body activities for which an opticalfiber is employed has been disclosed, for example, with JapaneseUnexamined Patent Application No. 5-312966, Japanese Unexamined PatentApplication No. 8-584 and the like.

The aforementioned technologies of a sensor are all based on a fact that“when an optical fiber is abruptly bent, a linearity of light surpassesa light enclosure effect of light of an optical fiber core, thusbringing about the loss of a light quantity due to the leakage oflight”. However, there remain several disadvantages such as the belowmentioned a, b and c.

a. An optical fiber needs to be bent abruptly in order that a loss isbrought about.

b. It becomes difficult to adjust a bending quantity due to a fact thata loss increases exponentially to the bend radius. This requires aspecially designed tool to obtain an appropriate bend quantity.

c. It is feared that a wire is broken or deteriorated due to its fatiguewhen it is abruptly bent.

On the other hand, with an optical fiber, it has been well known sincelong ago that the polarized wave conditions of the propagated lightchanges along with the changes of the shape of its bending. And,detecting systems for crime prevention have been developed with thisknowledge. For example, with Japanese Unexamined Patent ApplicationPublication No. 2000-40187, Japanese Unexamined Patent ApplicationPublication No. 2001-6055 and the like, it is so made that an opticalfiber is fitted to a fence and the like to sense invaders and raise analarm by means of detecting polarized wave fluctuations brought about byexternal forces applied to an optical fiber.

However, with Japanese Unexamined Patent Application Publication No.2000-40187 and the like, it is so constituted that an optical fiber issimply fitted to a fence for the purpose of sensing invaders fromoutside. Therefore, it is found difficult to apply it immediately formonitoring living body activities of a human. In addition, since it isalso so constituted that external forces of an invader is directlyapplied to an optical fiber, and no consideration is paid at all forenhancing the sensitivity of detecting fluctuations of polarized waveconditions due to changes of feeble pressure applied, thus making itdifficult to immediately apply it to a monitoring system for humanactivities.

Furthermore, because polarized wave conditions of light in an opticalfiber is generally random, a so-called polarized wave correction isrequired to use the polarized wave as a sensor. However, a polarizedwave correction is found to be time-consuming and the manufacturingcosts go up due to the reason that an apparatus for measuring polarizedwave fluctuations is so complicated.

Applicants of the present invention developed and disclosed a systemwith which a polarized wave quantity is detected simply and with highsensitivity to solve problems pertaining to corrections of a polarizedwave without requiring corrections of a polarized wave (JapaneseUnexamined Patent Application Publication No. 2004-108918 and JapaneseUnexamined Patent Application Publication No. 2004-184323). The presentapplication allows that all human activities and movements includingrespiration and pulsation are detected (sensed) with high accuracy bymeans of applying the system for detecting said quantity of polarizedwave fluctuations to a system for monitoring activities and movements ofa human.

[Patent Document 1] Japanese Unexamined Patent Application PublicationNo. 5-312966

[Patent Document 2] Japanese Unexamined Patent Application PublicationNo. 8-584

[Patent Document 3] Japanese Unexamined Patent Application PublicationNo. 2000-40187

[Patent Document 4] Japanese Unexamined Patent Application PublicationNo. 2001-6055

[Patent Document 5] Japanese Unexamined Patent Application PublicationNo. 2004-108918

[Patent Document 6] Japanese Unexamined Patent Application PublicationNo. 2004-184223

OBJECTS OF THE INVENTION

It is the principal object of the present invention to provide a methodfor monitoring living body activities, and an optical fiber type flatshaped body sensor, a garment styled optical fiber type flat shaped bodysensor and a human body fitted optical fiber type flat shaped bodysensor used for the same to solve the aforementioned problems with theknown monitoring system for living body activities such as:

a. with a system for which a piezoelectric sensor or a vibration typesensor is used, it is not possible to monitor respiration, pulsation andthe like at low costs and with high accuracy,b. with a system for which an optical fiber is used as a sensor, it isdifficult to detect changes of feeble living body activities (such as,for example, respiration and pulsation) due to the reason that the lossof a light quantity brought about by abrupt bending of an optical fiberis made to be a detection element, and there exists a risk of a wirebeing broken or deteriorated, andc. there exists a problem with low detection sensitivity because amonitoring system for which fluctuations of a polarized wave is made tobe a detection element is mainly used for preventing invasion fromoutside, thus making it possible that they are used in the same way theconventional cloth made sheet is used, and a quantity of polarized wavefluctuations of propagated light in an optical fiber brought about byhuman activities such as respiration, pulsation and the like can bedetected with high sensitivity by sensing human activities with highaccuracy, and also making it possible that they are manufactured at lowcosts.

More specifically, it is the principal object of the present inventionto provide:

a. an optical fiber type flat shaped body sensor which allows to monitorpatients and the like without adversely affecting them while sleeping byintegrating a flat shaped body such as a cloth made sheet with theaforementioned optical fiber by making use of features of a light andthin thread-like optical fiber, thus making it possible that the opticalfiber is used in such a way the conventional cloth made sheet is used,b. an optical fiber type flat shaped body sensor which can be adaptableto a variety of human activities under many possible circumstantialsettings and forms (for example, a bed, a Tatami-mat, a bed sheet, aseat cover, a stretcher, a hammock, a carpet, a mat, clothes and thelike along with human activities, andc. a method for monitoring living body activities which makes itpossible that various kinds of vibrations having a wide variety ofvibration characteristics are detected with high accuracy by using apolarized wave fluctuation measuring apparatus and by treating signalsthereof in a special way even though there exist the case of humanactivities or movements which bring about obvious changes in a flatshaped body like a sheet and the like, and the case of human activitiesor movements such as respiration or pulsation which conversely bringabout little change in the form of a flat shaped body, also there arecases with which vibrations become feeble as when vibrations make adirect contact with a fiber, when changes of a flat shaped body lead tochanges of changes of a fiber, or when changes of a flat shaped body anda fiber are brought about by way of a pad.

DISCLOSURE OF THE INVENTION

To overcome difficulty with the aforementioned inventions, the presentinvention as claimed in claim 1 is fundamentally so constituted thatwith a method for monitoring the existence of movements of a human orliving body activities under living circumstances while sleeping on bed,Futon-bed, pad, Tatami-mat and the like, human activities or movementsare discriminated with the detected value of polarized wave fluctuationsin a manner that a flat shaped body is either spread or covered with anoptical fiber type flat shaped body sensor in which an optical fiber isfitted to or mingled with, and light is emitted into the aforementionedoptical fiber from a light source, thus changes of a polarized wave oflight propagated in an optical fiber brought about by changes of a formof the aforementioned optical fiber type flat shaped body sensor alongwith living body activities or movements of a human being detected witha polarized wave fluctuations measuring apparatus.

The present invention as claimed in claim 2 according to claim 1 is somade that a flat shaped body is to be any of a sheet, a bed sheet, ablanket, a mat, a pad, a Tatami-mat, a floor cover or a carpet.

The present invention as claimed in claim 3 according to claim 1 is somade that periodic vibrations specific to respiration or pulsation aredetected with the sum of the power spectrum by using a measuringapparatus for polarized wave fluctuations of light propagated in anoptical fiber and by time wave forms of 3 stokes parameters thatrepresent polarized wave conditions of light being transformed withFourier Transform respectively.

The present invention as claimed in claim 4 according to claim 1 orclaim 3 is so made that it becomes possible that by using a measuringapparatus for polarized wave fluctuations of light propagating in anoptical fiber, living body activities or movements of a human aredetected at high velocity and with high sensitivity in the manner thatthe difference between the present value of a polarized wave conditionparameter expressed by 3 stokes parameters, a polarized wave ellipse ora phase difference between DC/AC polarized waves and the like and apolarized wave condition parameter found ¼-½ hours before the specificperiodicity of vibration obtained with the aforementioned claim 3 iscomputed as a polarized wave fluctuation quantity.

The present invention as claimed in claim 5 according to claim 3 orclaim 4 is so made that it becomes possible that highly sensitive livingbody activities or movements of a human are detected in the manner that,at a time of computing a polarized wave fluctuation quantity, apolarized wave condition parameter obtained from the sampling isprocessed for a moving average, and the width of the moving average ismade to be ¼-½ the vibration periodicity obtained in claim 3 and thelike, thus removing random noises in signals effectively.

The present invention as claimed in claim 6 according to claim 1 orclaims 3 to 5 is so made that not only the existence of human activitiesbut also the type of human activities is discriminated by utilizing thefacts that in the event of body movements such as tossing and turningthe polarized wave fluctuation signal is aperiodic but the fluctuationrange is wide, while in the event of respiration at rest or pulsationduring no respiring the fluctuation range is narrow but periodic.

The present invention as claimed in claim 7 according to claim 3 is somade that it becomes possible that signals are transmitted from a humanto a measuring apparatus for polarized wave fluctuations with patternsmade when a human kicks or knocks any given side of a flat shaped bodyintentionally.

The present invention as claimed in claim 8 according to claim 1 is somade that a plurality of optical fiber type flat shaped body sensors ora plurality of optical fibers in blocks are monitored in sequence withone set of a measuring apparatus for polarized wave fluctuations bymeans that a light source apparatus and a measuring apparatus areswitched and connected to a plurality of optical fibers of optical fibertype flat shaped body sensors or to a plurality of optical fibers inblocks in an optical fiber type flat shaped body sensor.

The present invention as claimed in claim 9 according to claim 1 is somade that a plurality of optical fibers of a flat shaped body sensor ora plurality of blocks in an optical fiber type flat shaped body sensorare monitored in sequence with one set of a measuring apparatus forpolarized wave fluctuations by means that light is emitted to aplurality of optical fibers of an optical fiber type flat shaped bodysensors or a plurality of optical fibers in blocks in an optical fibertype flat shaped body sensor from a wavelength variable light source byswitching optical fibers in sequence using a wavelength separationfilter.

The present invention as claimed in claim 10 according to claim 1 is somade that a specific block of an optical fiber is discriminated formonitoring by means that a plurality of filters with which a specificwave length such as an optical fiber diffraction is reflected areincorporated at some midpoint of an optical fiber of an optical fibertype flat shaped body sensor, thus the wave length of a light sourceapparatus being changed.

The present invention as claimed in claim 11 according to claim 1 is somade that a specific block of an optical fiber is discriminated formonitoring with the delay time of light dispersed in the optical fiberby transmitting an optical pulse from one end of an optical fiber of anoptical fiber type flat shaped body sensor.

The present invention as claimed in claim 12 according to claim 1 is somade that movements of a human are monitored from a distance by makingan optical fiber of an optical fiber type flat shaped body sensor acommunications optical fiber and by connecting said optical fiber to thecommunications optical fiber.

The present invention as claimed in claim 13 is fundamentally soconstituted that shape changes of any part of the outer surface of aflat shaped body are reflected by means of making optical fibers affixedand run throughout the flat shaped body.

The present invention as claimed in claim 14 according to claim 13 is somade that the similar use-feelings as those obtained with cloth madesheets while in bed are secured in the manner that covered and extremelythin optical fibers are sewed up throughout a flat shaped body, thusweight, thickness and flexibility of an optical fiber incorporated flatshaped body remaining unchanged with those of an ordinary cloth madesheet.

The present invention as claimed in claim 15 according to claim 13 orclaim 14 is so made that a flat shaped body is made to be any one of asheet, a bed sheet, a quilt cover, a blanket, a mat, a pad, aTatami-mat, a floor cover or a carpet.

The present invention as claimed in claim 16 according to claim 13 orclaim 14 is so made that sensitivity brought about with polarized wavefluctuations is raised to changes in form of an optical fiber type flatshaped body sensor by means of making the form of affixing or sewing upof an optical fiber so complex like linear shaped, wave shaped or loopshaped.

The present invention as claimed in claim 17 according to claim 13 orclaim 14 is so made that sensitivity brought about with polarized wavefluctuations is raised to changes in form of an optical fiber type flatshaped body sensor by means of the number of conductors of an opticalfiber being multiplied.

The present invention as claimed in claim 18 according to claim 13 orclaim 14 is so made that sensitivity brought about with polarized wavefluctuations is raised to changes in form of an optical fiber type flatshaped body sensor by means of a reflection mirror being placed on oneside of an optical fiber so that light signals are transmitted in theoptical fiber with to-and-from movements.

The present invention as claimed in claim 19 according to claim 13 orclaim 14 is so made that an optical fiber type flat shaped body sensoris processed to make a cover for a Futon-bed, a quilt, a mat, a sofa andthe like.

The present invention as claimed in claim 20 according to claim 19 is somade that a water tight process is conducted with a vinyl cover and thelike.

The present invention as claimed in claim 21 is a garment styled opticalfiber type flat shaped body sensor with which any changes in form of anypart of a human body are reflected to changes in form of an opticalfiber by means of making optical fibers sewed up in or affixed toclothes such as a pajama, a night wear, a patient dress, a garment wornby the monitored and the like which are all put on a human body while inbed, during a medical test being conducted, a human being monitored foractivity conditions and the like.

The present invention as claimed in claim 22 is a human body fittedoptical fiber type flat shaped body sensor with which any changes inform of any fitted part are reflected to changes in form of an opticalfiber by means of an optical fiber being sewed up in or affixed to ahuman body fitted pad in the shape of a stomach band, a bandage or asheet to be affixed.

EFFECT OF THE INVENTION

The present invention makes it possible that movements of a patient andthe like is monitored under normal conditions in a daily life withoutgiving the users of an optical fiber type flat shaped body sensorstrange or abnormal feelings at all due to the reason that said opticalfiber type flat shaped body sensor is formed with light weight opticalfibers with a small diameter being integrated with and affixed to a flatshaped body such as a cloth made sheet and the like.

The present invention makes it possible that a wide range of vibrationin intensity from human activities like bed going and bed leaving torespiration and pulsation is detected with high accuracy by using onemeasuring apparatus for polarized wave fluctuations, and the presentinvention is applicable to all flat shaped bodies such as a bed, a mat,a blanket, a bed sheet, a quilt cover and the like due to the reasonthat a fluctuation quantity of polarized wave conditions of lightpropagated in an optical fiber brought about by living body activitiesand respiration, pulsation and like of a human body can be detected inreal time, and also sensitivity can be upgraded by raising the ratio ofa detected value and noises.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory drawing to show one of embodiments of a methodfor monitoring living body activities.

FIG. 2 is an explanatory drawing to show one example how an opticalfiber type flat shaped body sensor is used wherein (a) designates whenit is used on a floor top, (b) when it is used on a bed, and (c) when itused as a top cover.

FIG. 3 is an explanatory drawing to show polarized wave fluctuations oflight passing through an optical fiber wherein (a) shows polarized waveconditions of the plane of emission (to be ellipse-shaped) by stress (F)being applied, (b) deformed conditions of an optical fiber 2 due toliving body activities of a human, and (c) a relative relationshipbetween the direction of vibration and stress F which bring about themaximum polarized wave fluctuations and the form of an optical fiber 2,respectively.

FIG. 4 is an explanatory drawing of a measuring apparatus for polarizedwave fluctuations 5 wherein (a) is an explanatory drawing of an entirebasic constitution, (b) an explanatory drawing of the basic constitutionof a polarized wave condition detection part and (c) an explanatorydrawing to show how a polarized wave condition detection part and apolarized wave fluctuation quantity detection part are connected.

FIG. 5 shows definitions of the display of polarized wave fluctuationsand a polarized wave fluctuation quantity with a stokes parameterdetected by a polarized wave condition detection part of a measuringapparatus for polarized wave fluctuations respectively.

FIG. 6 is an explanatory drawing to show a concept of a moving averagetreatment of a polarized wave fluctuation quantity β.

FIG. 7 is an explanatory drawing to show a concept of a fluctuationcomputation width treatment of a polarized wave fluctuation quantity β.

FIG. 8 is a plan view to show the first embodiment of an optical fibertype flat shaped body sensor.

FIG. 9 is an explanatory drawing to show the second embodiment of anoptical fiber type flat shaped body sensor.

FIG. 10 is an explanatory drawing to show the third embodiment of anoptical fiber type flat shaped body sensor.

FIG. 11 is an explanatory drawing to show other embodiments of a methodfor monitoring living body activities.

FIG. 12 is an explanatory drawing to show further other embodiments of amethod for monitoring living body activities.

FIG. 13 is an explanatory drawing to show another embodiment of a methodfor monitoring living body activities.

FIG. 14 is an explanatory drawing to show further another embodiment ofa method for monitoring living body activities.

FIG. 15 is an embodiment to show a relationship between living bodyactivities of a test subject and a polarized wave fluctuation quantityA, a degree of polarized light (DOP) and the like.

FIG. 16 shows the results of the FFT-analysis of a stokes parametershown in FIG. 15 by using equation (5). FIG. 16( a) shows the analyticalresults for 51.2 sec with a posture of being laid on one's back at rest,and (b) shows the analytical results for 25.6 sec with a posture ofbeing laid on one's side at rest respectively.

FIG. 17 shows the results of the FFT-analysis of Test Case 19 (KW401)shown in Table 1 by using equation (5). FIG. 17( a) shows the analyticalresults for 25.6 sec with a posture of being laid on one's back at restunder normal breathing conditions, and (b) shows the analytical resultsfor 6.4 sec with a posture of being laid on one's side at rest under nobreathing condition (no respiration).

FIG. 18 shows the difference in signals when values m and n are changedby expanding a longitudinal axis so that fluctuations during the stillperiod can be clearly seen with regard to the wave forms of a polarizedwave fluctuation quantity β in FIG. 15.

FIG. 19 is a plan view to show an example of a garment styled opticalfiber type flat shaped body sensor.

FIG. 20 is wave forms of an embodiment which show a relationship betweenrespiration conditions of a human with a garment styled optical fibertype flat shaped body sensor and a polarized wave fluctuation quantityand a stokes parameter.

LIST OF REFERENCE NUMERALS AND CHARACTERS

-   -   H Human    -   1 Optical fiber type flat shaped body sensor    -   2 Optical fiber    -   3 Cloth made sheet (flat shaped body)    -   4 Light source apparatus    -   5 Measuring apparatus for polarized wave fluctuations    -   6 Floor    -   7 Bed    -   8 Mat    -   9 Pad    -   10 Cloth made sheet    -   11 Blanket    -   12 Polarized wave condition detection part    -   13 Polarized wave fluctuation quantity detection part    -   S₁,S₂,S₃ Stokes parameters    -   β Polarized wave fluctuation quantity    -   14 Polarized wave branching element    -   15 Rotary polarization element    -   16 λ/4 plate    -   17 Photo receptor    -   18 Reflection mirror    -   19 Photo circulator    -   20 Optical fiber selector switch    -   21 Wavelength variable type light source    -   22 Wavelength separation filter    -   23 Filter    -   24 Connector part or partial reflection element    -   25 Pulse light source apparatus    -   26 Garment styled optical fiber type flat shaped body sensor

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments in accordance with the present invention arehereinafter described with reference to the drawings. FIG. 1 is anexplanatory drawing to show one example of embodiments of a method formonitoring living body activities in accordance with the presentinvention. FIG. 2 is an explanatory drawing to show one example of usesof an optical fiber type flat shaped body sensor.

Referring to FIG. 1, 1 designates an optical fiber type flat shaped bodysensor, 2 an optical fiber, 3 a cloth made sheet (flat shaped body), 4 alight source apparatus, 5 a measuring apparatus for polarized wavefluctuations.

Referring to FIG. 2, 6 designates a floor, 7 a bed, 8 a mat, 9 a pad, 10a cloth made sheet, 11 a blanket and H a human.

The aforementioned optical fiber type flat shaped body sensor 1 is madewith an optical fiber 2 being fixed to the entire surface of a clothmade sheet. As described later, there exist a variety of structures,forms and methods of fixing of an optical fiber to be used.

As shown in FIG. 2, said optical type flat shaped body sensor 1 is usedby fitting it on the top of a bed or a floor 6, or in the form ofcovering a human H with it. Also, as described later, it is possiblethat said optical fiber type flat shaped body sensor 1 is not only usedin the form of a sheet or a spread, but also used in the form of apillow case or a cover sheet for a Futon-mat or in the form of a pajama,a night wear, an underwear and the like.

As shown in FIG. 1, a method for monitoring living body activities isbased on that the stress such as vibration, pressure or the like broughtabout by living body activities (bed-going, bed-leaving, respiration,pulsation and the like) of a human H is applied to an optical fiber 2 ofan optical fiber type flat shaped body sensor 1, thus polarized wavefluctuations brought about on light propagated in an optical fiber 2being able to be detected by a measuring apparatus for polarized wavefluctuations 5. FIG. 3 is an explanatory drawing to show the concept ofthe aforementioned polarized wave fluctuations, and FIG. 4 is anexplanatory drawing to show the principal constitution of theaforementioned measuring apparatus for polarized wave fluctuations 5.

Namely, when light propagating in an optical fiber 2 is applied by amagnetic field, pressure, vibration, temperature changes and the like,or, for example, an optical fiber 2 is applied by stress F as shown inFIG. 3( a), an incident polarized wave plane A is made to be ellipticlike an emitting polarized wave plane A′. A polarized wave planementioned here means a vibration plane of an electric field when lightis taken as an electromagnetic wave.

Generally, polarized wave fluctuations are detected by means of aconstituent only in the horizontal direction toward an emittingpolarized wave plane A′ being taken out normally by using a polarizer,and changes of a polarized wave are detected as changes oflight-strength. However, polarized wave conditions change at randomduring propagation. Therefore, in order that the maximum degree ofmodulation (strength changes) can be obtained at the emission end, it isfound necessary that a polarizer and a polarized wave adjuster arerotated and adjusted for detection. With the present invention, suchadjustments are not needed, and it is so made, however, that stokesparameters are measured as described later.

The indication of polarized wave conditions of light wave signals isdone normally with stokes parameters S₁, S₂, S₃. As described later, theindication is performed with values S₁, S₂, S₃ (stokes parameter S₁ is alinear polarized wave in a horizontal

vertical direction, stokes parameter S₂ is a linear polarized wave in a+45 degree

−45 degree direction, and S₃ is a circular polarized wave of a rightturn

a left turn) corresponding to each light strength constituent directlymeasured with three kinds of polarized filters on Poincare's sphericalsurface.

FIGS. 3( a) and (b) show a relationship between the direction of stressF applied to an optical fiber 2 and the width of polarized wavefluctuations It has empirically found polarized wave fluctuationsbrought about by vibration or bend force F applied to an optical fiber 2have been dependent largely on the form of an optical fiber, that is,polarized wave fluctuations are found to be relatively large whenvibration is applied in a perpendicular to the original bent face of anoptical fiber 2.

FIG. 4 is an explanatory drawing to show a basic configuration of ameasuring device for polarized wave fluctuations 5 in use with thepresent invention. Referring to FIG. 4( a), 12 designates a polarizedwave condition detection part, 13 a polarized wave fluctuation quantitydetection part, and S a polarized wave fluctuation quantity detected.

FIG. 4( b) is an example of a basic configuration of an elementincorporated into a polarized wave condition detection part 12, wherein14 designates a polarized light branching element, 15 a rotarypolarization element, 16 a λ/4 plate and 17 a photo receptor. Theaforementioned polarized light branching element 14 is an element totake out a horizontal polarized light constituent at the branching ratioof approximately 1˜5%. A rotary polarization element 15 is so made thatthe plane of a polarized light is rotated for 45 degree. Furthermore, aλ/4 plate is so made that a doubly refracting principal axis thereof isset at 45 degree from a horizontal face.

Generally, it is needed, as mentioned before, that a vibration-centeredposition on the sphere and the direction of vibration are adjusted todetect polarized wave fluctuations with high sensitivity. However, it isfound not easy to make such adjustments in a short period of time.

Thus, with the present invention, it is so made that a polarized wavefluctuation quantity β is computed with three constituents of apolarized wave S₁, S₂, S₃.

Namely, output signals V₁, V₂, V₃, V₀ of each photo receptor 17 arecorrected for sensitivity differences with a light branching element andthe like (that is, correction is made so that V₁, V₂, V₃ become thevalues of 0˜V₀ depending on polarized wave conditions), thus a polarizedwave fluctuation quantity β being computed by using stokes parametersS₁, S₂, S₃ obtained as Sj=2Vj/V₀−1 (where j=1, 2, 3).

Concretely, as shown in FIG. 5, standard conditions of polarized wavefluctuations are set as S₁₀, S₂₀, S₃₀, and assuming stokes parameterswhich show polarized wave conditions measured are S₁, S₂, S₃, a trianglewith 2 vertices [V₁, V₂, V₃] [S₁₀, S₂₀, S₃₀] and an origin [0, 0, 0]becomes an isosceles triangle as in FIG. 5, and its vertex angle β isexpressed by the following equations:

β=2 sin⁻¹(dL/2)  (1)

dL=√(dS ₁ ² +dS ₂ ² +dS ₃ ²)  (2)

dSj=Sj−Sj ₀  (3)

(where j=1, 2, 3)

With the present invention, it is defined that the angle β is apolarized wave fluctuation quantity. Here, dsj is the change quantitiesof each coordinate, and dL is equivalent to a travel distance of acoordinate point. The distance from a coordinate original point to acoordinate point is the degree of polarized light (DOP=S₁+S₂+S₃).However, in the case that monochromatic light is used, it is that DOP=1.

Referring to FIG. 5, θ is a so-called polarized wave principal axisazimuth, and ε is an elliptic rate angle.

A polarized wave fluctuation quantity β expressed by the above shownequation (1) is computed in real time with a polarized wave fluctuationquantity detection part 13 in FIG. 4( a) without so-called polarizedwave adjustments. Said polarized wave fluctuation quantity detectionpart 13 is constituted as a digital (or analogue) type computationapparatus.

Concretely, as shown in FIG. 4( c), light is converted to electricsignals with each photo receptor 17, amplified with a log amplifier,AD-converted and transmitted to the PC the mediation of the USBinterface. On the PC side, stokes parameters S₁, S₂, S₃, the degree ofpolarized light (DOP) and a polarized wave fluctuation quantity β arecomputed, and what are computed are stored in a hard disc together withthe strength of light, time data, key events (key entry of conditionchanges and the like for a memo)

The range of a log amplifier is 30 dB, the resolving power of an ADconverter is 12 bit (value of 1500 per a digit) and the velocity is 10kHz. The transmission period of the USB is 0.01 sec. It is soconstituted that an average is obtained for every 10 data, thuscomputation and storage being performed with the periodicity of 0.1 secafter making averaged for every 10 data.

With the aforementioned polarized wave fluctuation quantity detectionpart 13 in FIG. 4, it is so constituted that a polarized wavefluctuation quantity β is computed with equations (1), (2), (3) by usingstokes parameters S₁, S₂, S₃. However, as mentioned later, in the casethat a survey on contents of feeble vibration (for example, feeble andperiodic vibration wave forms such as those of respiration and pulsationof a human) is conducted, it is considered that feeble vibration can beeasily discriminated with the wave forms of stokes parameters S₁, S₂, S₃than a polarized wave fluctuation quantity β. So, the FFT (Fast FourierTransform) analysis of the stokes parameters was conducted to determinethe vibration detection limit, and based on what are found theimprovements of detection sensitivity have been achieved by setting astandard of a polarized wave fluctuation quantity S and doing a movingaverage treatment.

As shown in FIG. 5 and the like, the aforementioned polarized wavefluctuations are expressed by vibration on the spherical surface of aradius 1 when stokes parameters S₁, S₂, S₃ are expressed with the3-dimensional orthogonal coordinates of x, y, z, and a polarized wavefluctuation quantity B is expressed by the afore stated equations(1)˜(3).

To obtain the fluctuation width (peak to peak) of periodic vibration,both ends of vibration can be replaced with S1, S2, S3 and S10, S20, S30as shown in FIG. 5. That is, in the case of feeble vibration, the aforeshown equation (1) becomes as:

βp·p=dL [rad]  (4)

(in the case of [degree] unit, dL*180/π)

Now, with the vibration of single frequency F, assuming that thevibration widths of stokes parameters are dS_(1f), dS_(2f), dS_(3f) whenthere exists no phase difference with the vibration of stokesparameters, equation (2) can be written as:

dL _(f) ² =dS _(1f) ² +dS _(2f) ² +dS _(3f) ²  (5)

Here, ½ of dS (j=1, 2, 3) is equivalent to a vibration power with afrequency f of Sj.

Therefore, the power spectrum can be obtained with the aforementionedFFT on three wave forms of stokes parameters S1, S2, S3 measured, thusmaking it possible that evaluation is achieved with the total valuethereof.

Namely, the power spectrum can be obtained by treating three stokesparameters S₁, S₂, S₃ with the FFT, and its total Q is obtained asQ=ζS₁+ζS₂+ζS₃, thus an amplitude Lpp of a frequency constituent of avibration peak being obtained as Lpp=√(2Q). The concept of said analysisby the FFT is substantially same as that of an analysis of a polarizedwave fluctuation quantity β shown in the afore stated equations (1)˜(3).

Due to the reason that polarized wave fluctuation quantity β is computedwith the difference between stokes parameters at the present time andstokes parameters at the time antecedent to the specified time (astandard value), detection of fluctuations can be performed at ease, andan instantaneous response property (a real time property) is foundexcellent. However, when a time span of computation is made too shortfor comparatively slow vibration, a polarized wave fluctuation quantityβ becomes hidden with noises for the reason that the width of changes ofstokes parameters caused by the vibration becomes smaller than that withnoises.

In the case of the waveform of, for example, pulsation as describedlater, the existence of the vibration can be identified when the entirewaveform is found, but it will be difficult to see instantaneous changeswith the difference between after- and before-samplings.

Furthermore, in order to raise the signal and noise ratio SNR of apolarized wave fluctuation quantity β, it is required that a. a movingaverage treatment of stokes parameters is optimized (n) and that b. thetime width for computing β is optimized (m).

To do so, the following two treatments are conducted with the presentinvention.

a. For the optimization of a moving average treatment of stokesparameters, the k-th sampling dada, Sj(k)(j=1, 2, 3) of stokesparameters are transformed to the averaged Sj(k)a in the case of thenumber of a moving average=n as below:

$\begin{matrix}{{{{Sj}(k)}a} = {\left( {l/n} \right)*{\sum\limits_{i = 0}^{n - 1}{{Sj}\left( {k - i} \right)}}}} & (6)\end{matrix}$

Here, n=1 is for the case of (Sj(k)a=Sj(k)) without being averaged.

b. Next, for the optimization of the time width for a polarized wavefluctuation quantity β, in the case of the computation width of β, withequations (1)˜(3), β(k) obtained by the k-th data Sj(k) is made to be astandard of stokes parameters antecedent to the m sample from the stokesparameters of the present time, and equation (3) is replaced as below:

dSj(k)=Sj(k)−Sj(k−m)

Here, Sj(k) can be Sj(k)a averaged with a.

FIG. 6 and FIG. 7 are explanatory drawings of the aforementioned amoving average treatment and a fluctuation quantity computation width.As apparent from FIG. 6 and FIG. 7, with the moving average treatment, arise time is delayed by the moving average number n, and a signal peakbecomes smoothened, thus being small when a moving average number n isexcessive, but a fluctuation quantity computation width m is notaffected by this, thus there being no delay with a rise time and thepeak not becoming small even when a fluctuation quantity computationwidth m is excessive. However, when an original waveform is observed asthe periodic vibration, there is caused a delay by a fluctuationquantity computation width m, and the waveform is disrupted in the casethat a fluctuation quantity computation width m is excessive. When afluctuation quantity computation width m is small, the amplitude becomessmaller than the original waveform, thus a possibility of it beingburied into the noise.

Accordingly, it is recommended that a moving average number n and anaverage computation width m are set shorter than ½ the assumed vibrationperiodicities. With the embodiment, a sampling periodicity is 0.1sec/sample, and the effectiveness will be less than 25 sample if thevibration periodicity of respiration is approximately 5 sec.

EMBODIMENT 1

FIG. 8( a)-FIG. 8( d) show preferred embodiments of an optical fibertype flat shaped body sensor 1. As shown in FIG. 3( b) and FIG. 3( c),polarized wave fluctuations caused by vibration and bend stress Fapplied to an optical fiber 2 become relatively large when vibration andthe like are applied in the direction perpendicular to the original bendplane of an optical fiber 2. Therefore, 4 different types of sensors8(a)˜8(d) have been manufactured.

An optical fiber 2 has been affixed to a cloth made sheet 3, and it isso constituted that, with this case, an single mode optical fiber 2 witha covered outer diameter of approximately 0.5 mm and a conductor cladwhich diameter is 0.125 mm φ is fixed with a synthetic resin madeadhesive to a flat shaped body made of a blended cloth of a syntheticresin and a natural fabric.

Affixation of an optical fiber 2 to a flat shaped body (a cloth madesheet 3) can be achieved with any method such as being sewed in a clothmade sheet or being caught between 2 thin cloth made sheets.

An optical fiber 2 can be used as bare. There is no need to say that theouter surface of an optical fiber 2 can be thinly covered.

Furthermore, affixation of an optical fiber 2 (flat shapes in a state ofadhesion) can be of any form such as a loop shape (FIG. 8( c)), a waveshaped (FIG. 8( d)) or any other types.

EMBODIMENT 2

FIG. 9 shows a preferred embodiment in the event that the structure ofan optical fiber 2 in FIG. 8 is made to be of a multi-conductor type(the number of conductors n) with which sensitivity brought about bypolarized wave fluctuations to changes of shapes of a flat shaped bodysensor 1 is improved. Here, a light source apparatus 4 and a measuringapparatus for polarized wave fluctuations are connected with the endpart of one side of a multi-conductor type optical fiber 2.

EMBODIMENT 3

FIG. 10 shows the method of sensitivity brought about by polarized wavefluctuations to changes of shapes of a flat shaped body sensor 1 beingraised by means that a reflection mirror 18 is installed at the end partof one side of an optical fiber 2 in order that light wave signals aretransmitted to and fro. In FIG. 10, 19 designates an optical circulator.An optical coupler can be used as a substitute for an optical circulator19.

EMBODIMENT 4

With the afore shown embodiments 1˜3, a flat shaped body sensor 1 isformed in a quadrangle shaped sheet (a flat shaped body). There is noneed to say that a flat shaped body sensor 1 can be utilized by means ofthe sheet being integrally processed to make a cover for a Futon-bed, aquilt, a mat, a sofa and the like.

Also, there is no need to say that a flat shaped body sensor 1 withEmbodiment 1˜Embodiment 3 can be made watertight by using a vinyl cover.

Furthermore, by using a flat shaped body sensor 1 with Embodiment1˜Embodiment 3, clothes such as a pajama or a night wear can be formed,or an optical fiber 2 can be adhered to clothes separately prepared, tomake a garment styled optical fiber type sensor with which any changesof a shape of a human body can be detected as changes of a shape of anoptical fiber 2.

In addition, by means of an optical fiber being sewed in a pad shapedbody made in the manner that it is fitted directly to the outer surfaceof a human body, it becomes possible to make a human body fitted opticalfiber type sensor which allows that any changes of a form of the partfitted to a human body can be reflected to the changes of a form of anoptical fiber.

EMBODIMENT 5

FIG. 11 shows the case wherein, by using a measuring apparatus forpolarized wave fluctuations 5, a plurality of optical fiber type flatshaped body sensors or a plurality of blocks in an optical fiber typeflat shaped body sensor can be monitored in sequence with an opticalfiber selector switch 20. FIG. 11( a) and FIG. 11( b) are formed as atransmittance type one and a reflectance type one respectively.Referring to FIG. 11( a), 19 is an optical circulator.

EMBODIMENT 6

FIG. 12( a) and FIG. 12( b) are other preferred embodiments to show amethod for monitoring living body activities, wherein a light sourceapparatus 4 is made to be a wavelength variable type light source 21,and a wavelength separation filter 22 is used as a substitute for anoptical fiber selector switch 20 so that by using one set of a measuringapparatus for polarized wave fluctuations 5, polarized wave fluctuationsof a plurality of optical fiber type flat shaped body sensors 1 can bedetected in sequence, or a plurality of blocks of a flat shaped bodysensor 1 can be detected individually in sequence. FIG. 12( a) and FIG.12( b) are constituted as a transmittance type one and as a reflectancetype one respectively.

EMBODIMENT 7

FIG. 13 shows a preferred embodiment of another method for monitoringliving body activities, wherein a plurality of filters 23 allowing toreflect only a certain wavelength such as an optical fiber diffractiongrating are incorporated at some midpoint in the optical fiber 2, thusmaking it possible that a specific block of an optical fiber 2 isindividually discriminated and monitored.

EMBODIMENT 8

Referring to FIG. 14, it is so constituted that a plurality ofconnectors or partial reflection elements 24 are installed at somemidpoint in an optical fiber, and photo pulse signals are transmittedfrom a pulse light source apparatus 25, thus making it possible that aplurality of blocks of an optical fiber 2 are discriminated andmonitored with the delay time of dispersed light in an optical fiber 2.

With the aforementioned Embodiment 1˜Embodiment 8, it is so constitutedthat a light source apparatus or a measuring apparatus for polarizedwave fluctuations 5 is directly connected to an optical fiber type flatshaped body sensor 1. However, in the case that a flat shaped bodysensor 1 and a measuring apparatus 5 and the like are separated over adistance, it is possible that a flat shaped body sensor 1 is constitutedby using an general communications purpose optical fiber so that a flatshaped body sensor 1 and a measuring apparatus for polarized wavefluctuations 5 an the like are directly connected through the mediationof a communications purpose optical fiber.

EMBODIMENT 9

TABLE 1 Measurement Test Conditions of Polarized Wave FluctuationQuantity Flat shaped body Conditions for sensor (Sheet type) lighttransmission Test case Usage Number of Light name Type patternconductors in use direction 1 W401 FIG. 8 (d) FIG. 2 (a) 4 1 way 2 W101FIG. 8 (d) ″ 1 1 way 3 L401 FIG. 8 (c) ″ 4 1 way 4 L101 FIG. 8 (c) ″ 1 1way 5 L102 FIG. 8 (c) ″ 1 Reflection 6 H401 FIG. 8 (b) ″ 4 1 way 7 H101FIG. 8 (b) ″ 1 1 way 8 H102 FIG. 8 (b) ″ 1 Reflection 9 V401 FIG. 8 (a)″ 4 1 way 10 V101 FIG. 8 (a) ″ 1 1 way 11 V102 FIG. 8 (a) ″ 1 Reflection15 BV402 FIG. 8 (a) FIG. 2 (b) 4 1 way 16 BV102 FIG. 8 (a) ″ 1 1 way 17BW401 FIG. 8 (d) ″ 4 1 way 18 BW101 FIG. 8 (d) ″ 1 1 way 19 KW401 FIG. 8(d) FIG. 2 (c) 4 1 wayAs shown in Table 1, by using an optical fiber type flat shaped bodysensor 1 in FIG. 8( a), (b), (c), (d) in conditions as FIG. 2( a), (b),(c), measurements were conducted for activities of a test subject with ameasuring apparatus for polarized wave fluctuations. As described later,FIG. 15 shows measured data under the measurement test conditions of No.1 in Table 1. With FIG. 15, on the vertical axis, Power represents thestrength of light, S₁, S₂, S₃ stokes parameters (3 constituents of apolarized wave), DOP a degree of polarized light, β a polarized wavefluctuation quantity, and key conditions of human activitiesrespectively,

TABLE 2 Results of Assessment by Direct Visual Check on Measured DataStrength of Actions Test case photo reception On back Tossing & On sideTossing & On back Get out name [mW] Go to bed at rest Turning at restTurning at rest of bed Remarks 1 W401 0.838 ⊚ ◯ ⊚ ◯ ⊚ — ⊚ 2 W101 2.436 ⊚◯ ⊚ Δ ⊚ Δ ⊚ 3 L401 0.117 ⊚ X ⊚ Δ ⊚ X ⊚ Big loss 4 L101 1.538 ⊚ X ⊚ Δ ⊚ X⊚ 5 L102 1.259 ⊚ ◯ ⊚ ◯ ⊚ X ⊚ 6 H401 0.206 ⊚ ◯ ⊚ X ⊚ Δ ⊚ Big loss 7 H1013.112 ⊚ ◯ ⊚ X ⊚ Δ ⊚ 8 H102 1.613 ⊚ ◯ ⊚ X ⊚ ◯ ⊚ 9 V401 1.772 ⊚ X ⊚ Δ ⊚ Δ⊚ 10 V101 2.674 ⊚ X ⊚ X ⊚ X ⊚ 11 V102 1.529 ⊚ Δ ⊚ X ⊚ X ⊚ 15 BV402 1.649⊚ Δ ⊚ X ⊚ Δ ⊚ 16 BV102 2.551 ⊚ Δ ⊚ X ⊚ X ⊚ 17 BW401 1.245 ⊚ ◯ ⊚ ◯ ⊚ ◯ ⊚18 BW101 2.903 ⊚ ◯ ⊚ ◯ ⊚ ◯ ⊚ Respiration Deep Intense Respiration HaltRespiration Halt Respiration Halt — Remarks 19 KW401 1.103 ⊚ Δ ⊚ Δ ⊚ Δ— * Existence of meaningful vibrations ⊚ Clearly seen ◯ Slightly seen ΔDifficult to judge X Not seen

From the results of the aforementioned measurements, whether or notmovements of a test object can be checked visually were judged on thedata. The results were as shown in Table 2.

Specifically, with the test No. 19 (when an optical fiber type flatshaped body sensor 1 is used instead of a cover blanket), a clearjudgment was possible on respiration or non-respiration of a test objectdirectly from a so-called raw data.

EMBODIMENT 10

By using a wave styled optical fiber type flat shaped body sensor 1shown in FIG. 1 in a form as shown in FIG. 2( a), an analysis wasconducted on a polarized wave fluctuation quantity β obtained from avariety of living body activities of a human H (a test object).

FIG. 15 shows the state of activities (key) of a test object (H) andstokes parameters S₁˜S₃, a degree of polarized waves (DOP), a polarizedwave fluctuation quantity β, the strength of light (Power) detected andcomputed by a measuring apparatus for polarized wave fluctuations 5,with which it is learned that the strength of light (Power) remains samebut stokes parameters S₁, S₂, S₃ and a polarized wave fluctuationquantity β are substantially changed. At the time of rest, there areseen periodic changes at some points of stokes parameters.

An optical fiber 2 of a flat shaped body sensor 1 is of 4-conductortype, and as shown in FIG. 9, its constitution is of a 2 reciprocationtype.

FIG. 16 shows the results of stokes parameters shown in FIG. 15 beingFFT-analyzed by using the aforementioned equation (5). FIG. 16( a) iswhat analyzed for 51.2 sec when laid on a back at rest, and (b) for 25.6sec when laid on a side at rest. A lateral axis is for frequencies,while a longitudinal axis is for power spectrum which numeric values aremade 10 times. For both there appeared strong spectrum in the vicinityof 0.2 Hz. Therefore, it can be judged that this is caused byrespiration.

FIG. 17 shows the results of a test case 19 shown in Table 1 beingFFT-analyzed by using the aforementioned equation (5). FIG. 17( a) iswhat analyzed for 25.6 sec when laid on a back at rest while normallyrespiring, and (b) for 6.4 sec when laid on a back at rest whilerespiration being halted (non-respiration). With (a), there appearedextremely strong in the vicinity of 0.2 Hz, with which it was easilyjudged that this was caused by respiration, while with (b) it wasconfirmed that there existed a peak in the vicinity of 1.1 Hz, withwhich it was learned that this was caused by pulsation.

With visual assessments in Table 2, polarized wave fluctuations at thetime of respiration being halted were too feeble to be recognized.However, it was confirmed with the analysis of the present inventionthat there existed signals.

In order to detect the existence of feeble vibration and its frequencieswith the aforementioned FFT analysis, a time required for the analysisis approximately 5 times the periodicity of vibration of the object (6sec for pulsation and 25.6 sec for respiration). Analysis of vibrationfrequencies and the like can not be performed with a polarized wavefluctuation quantity 3, but the existence of polarized fluctuations canbe instantaneously found because the time delay in computation becomeapproximately a moving average n of stokes parameters and the βcomputation width m.

Polarized wave fluctuations in FIG. 18 are equivalent to the case ofboth a moving average n and a β computation width m being 1. Theexistence of prominent actions such as tossing and turning, bed-in,bed-out and the like can be instantaneously found from the results.

Furthermore, FIG. 18 shows a up-scaled longitudinal axis of the waveformof a polarized wave fluctuation quantity β in FIG. 15.

Firstly, in the case of m=1 and n=1, it is difficult to identify thedifference between the noises at the time of non-signals before a humangoes to bed and the signals after being laid on a back at rest and beinglaid on a side at rest in bed.

Next, in the case of m=20 and n=1, there remain noises unchanged at thetime of non-signals before a human goes to bed, and there appearfluctuation signals distinctly when laid on a back at rest and also laidon a side at rest.

Furthermore, in the case of m=20 and n=10, noises reduce remarkably atthe time of non-signals, and signals at the time when laid on a back atrest and laid on a side at rest are clearly identified.

EMBODIMENT 11

FIG. 19 is a plan view of a garment styled optical fiber type flatshaped body sensor 16 in accordance with the present invention. Saidgarment styled optical fiber type flat shaped body sensor 26 is formedin the manner that the same optical fiber 2 as the one used for anoptical fiber type flat shaped body sensor 1 shown in FIG. 1 is fittedto a T-shirt made from a so-called natural or synthetic fabric.

More specifically, an optical fiber 2 with 1 conductor or 4 conductorsis affixed to the outer surface of a cotton made T-shirt. An opticalfiber 2 is affixed in the shape of the combination of a wave(3-reciprocation and 2-tire) type and a horizontal (3-reciprocation)type as shown in FIG. 19.

To conduct a test, conditions of respiration of a test object, a maleadult who wore said garment styled fiber type flat shaped body sensor 26were changed with 2 positions, sitting and lying using 2 garment styledoptical fiber type flat shaped body sensor 26, one with an optical fiberwith 1 conductor and the other with an optical fiber with 4 conductors,thus making 4 different cases in total.

The pattern of respiration was made to be a certain one applicable toall cases, normal respiration (30 sec)→respiration halted (10 sec)→deeprespiration (20 sec)→respiration halted (10 sec)→intense respiration (20sec).

FIG. 20 is the measurement results of the time wave forms of thestrength of light, stokes parameters S₁, S₂, S₃, and a polarized wavefluctuation quantity at the time of a lying position with a garmentstyled optical fiber type flat shaped body sensor equipped with an4-conductor optical fiber.

Changes caused by respiration were distinctly detected with thewaveforms of stokes parameters S1, S2, S3 or a polarized wavefluctuation quantity.

Periodic changes were observed when respired. When normal respiration,deep respiration and intense respiration were compared, changes with thedifferent velocities were also observed.

The magnitude of polarized wave fluctuations was found to be larger thanthat of a bed sheet (FIG. 18), and slightly smaller than that of a quiltcover when compared with the test results in the case of being used as abed sheet and a quilt cover with a 4-conductor and wave shaped opticalfiber. Same analysis was conducted on the aforementioned other 3 cases,and it was learned that polarized wave fluctuations caused byrespiration were able to be observed with any cases.

With the results in FIG. 20, it is assumed that such movements asrespiration and the like can be detected from polarized wavefluctuations with a human body fitted optical fiber type flat shapedbody sensor. For example, in the case of a human body fitted opticalfiber type flat shaped body sensor fitted to the chest area, it isunderstood that, because it can be fitted closely to the individual bodyshape when compared with the case of a garment styled one, polarizedwave fluctuations equivalent to or better than those of FIG. 20.

FEASIBILITY OF INDUSTRIAL USE

The present invention is mainly used for remote monitoring of patients,the cared and the like in nursing care facilities, hospitals and thelike. Also, it can be widely used for monitoring living activities ofanimals, plants and the like other than humans. It also makes possiblethat patients and the like in hospitals or nursing care facilities overthe wide area are intensively monitored by making use of a so-calledcommunications network.

1. A method for monitoring living activities comprising a method formonitoring the existence of movements of human or living body activitiesunder living circumstances while sleeping on a bed, Futon-bed, pad, orTatami-mat, the method comprising the steps of: disposing an opticalfiber type flat shaped body sensor comprising a flat shaped body and anoptical fiber fitted to or integrated with the flat shaped body so thatliving body activities or movements of a human being bring about chancesin form of the optical fiber type flat shaped body sensor; emittinglight into the optical fiber from a light source; producing fluctuationsin a polarized wave of light propagated in the optical fiber when livingbody activities or movements of the human being bring about changes inform of the optical fiber type flat shaped body sensor; detectingfluctuations in the polarized wave of light using a polarized wavefluctuations measurement apparatus; and discriminating human activitiesor movements using the detected fluctuations in the polarized wave oflight.
 2. The method for monitoring living body activities according toclaim 1, wherein the flat shaped body is selected from the groupconsisting of a sheet, a bed sheet, a blanket, a mat, a pad, aTatami-mat, a floor cover and a carpet.
 3. The method for monitoringliving body activities according to claim 1, wherein periodic vibrationsspecific to respiration or heart pulsation are detected using a sum of apower spectrum detected by the polarized wave fluctuations measuringapparatus and by time wave forms of three stokes parameters thatrepresent polarized wave conditions of light transformed using a FourierTransform, respectively.
 4. The method for monitoring living bodyactivities according to claim 3, wherein by using the polarized wavefluctuations measuring apparatus living body activities or movements ofthe human being are detected at high velocity and with high sensitivityso that a difference between a present value of a polarized wavecondition parameter expressed by three stokes parameters, a polarizedwave ellipse or a phase difference between DC/AC polarized waves and apolarized wave condition parameter found ¼ to ½ hours before theperiodic vibrations specific to respiration or heart pulsation iscomputed as a polarized wave fluctuation quantity.
 5. The method formonitoring living body activities according to claim 4, wherein highlysensitive living activities or movements of the human being are detectedso that, at a time of computing the polarized wave fluctuation quantity,the polarized wave condition parameter obtained from sampling isprocessed for a moving average, and the width of the moving average ismade to be ¼ to ½ the periodic vibrations specific to respiration orheart pulsation thereby removing random noise in signals employed fordiscriminating human activities or movements.
 6. The method formonitoring living body activities according to claim 1, wherein both theexistence of human activities and the type of human activities arediscriminated by utilizing the fact that for body movements selectedfrom the group consisting of tossing and turning, getting into bed andgetting out of bed, polarized wave fluctuations are aperiodic andfluctuation range is wide while for respiration at rest, or heartpulsation during periods of no respiration, the fluctuation range isnarrow and periodic.
 7. The method for monitoring living body activitiesaccording to claim 3, wherein when the human being intentionally kicksor knocks any given side of the flat shaped body, then signals aretransmitted by the polarized wave fluctuations measuring apparatus. 8.The method for monitoring living body activities according to claim 1,wherein a plurality of optical fiber type flat shaped body sensors or aplurality of optical fibers in blocks disposed in an optical fiber typeflat shaped body sensor are monitored in sequence by one polarized wavefluctuations measuring apparatus, wherein monitoring in sequence isprovided by a light source apparatus and the polarized wave fluctuationsmeasuring apparatus connected together so as to switch and connect tothe plurality of optical fiber type flat shaped body sensors or to theplurality of optical fibers in blocks.
 9. The method for measuringliving body activities according to claim 1, wherein a plurality ofoptical fibers of the optical fiber type flat shaped body sensor or aplurality of blocks in the optical fiber type flat shaped body sensorare monitored in sequence by one polarized wave fluctuations measuringapparatus, wherein light is emitted to the plurality of optical fibersof the optical fiber type flat shaped body sensor or to the plurality ofoptical fibers in blocks in the optical fiber type flat shaped bodysensor from a wavelength variable light source by switching opticalfibers in sequence using a wavelength separation filter.
 10. The methodfor monitoring living body activities according to claim 1, wherein aspecific block of the optical fiber is discriminated for monitoring by aplurality of filters, with which a specific wavelength is reflected,wherein the plurality of filters are incorporated at some midpoint ofthe optical fiber of the optical fiber type flat shaped body sensor sothat, wavelength of the light source is changed.
 11. The method formonitoring living body activities according to claim 1, wherein aspecific block of the optical fiber is discriminated for monitoringusing a delay time of light dispersed in the optical fiber bytransmitting an optical pulse from one end of the optical fiber of theoptical fiber type flat shaped body sensor.
 12. The method formonitoring living body activities according to claim 1, whereinmovements of the human being are monitored from a distance, wherein theoptical fiber type flat shaped body sensor comprises a communicationoptical fiber and the optical fiber is connected to the communicationsoptical fiber.
 13. An optical fiber type flat shaped body sensor,comprising: a flat shaped body; and one or mole optical fibers affixedto and running throughout the flat shaped body so that shape changes ofany part of an outer surface of the flat shaped body are reflected as ashape chance in form of one or more of the optical fibers.
 14. Theoptical fiber type flat shaped body sensor according to claim 13,wherein the sensor feels like, and is used in the same manner as, acloth made sheet, and is deployable in bed as a cloth made sheet,wherein extremely thin optical fibers are sewed up throughout the flatshaped body, so that weight, thickness and flexibility of the opticalfiber incorporated in the flat shaped body provides the sensor withessentially the same weight, thickness and flexibility as the cloth madesheet.
 15. The optical fiber type flat shaped body sensor according toclaim 13, wherein the flat shaped body is selected from the groupconsisting of a sheet, a bed sheet, a quilt cover, a blanket, a mat, apad, a Tatami-mat, a floor cover and a carpet.
 16. The optical fibertype flat shaped body sensor according to claim 13, wherein changes inform of the optical fiber type flat shaped body sensor reflected as theshape change in form of one or more of the optical fibers generates afluctuation in polarized light propagated in the one or mole opticalfibers, wherein sensor sensitivity brought about by polarized wavefluctuation is increased by affixing or sewing up of the one or moreoptical fibers with the flat shaped body so that the one or more opticalfibers forms a complex linear shape, a complex wave shape or a complexloop shape.
 17. The optical fiber type flat shaped body sensor accordingto claim 13, wherein changes in form of the optical fiber type flatshaped body sensor reflected as the shape change in form of one or moreof the optical fibers generates a fluctuation in polarized lightpropagated in the one or more optical fibers, wherein sensor sensitivitybrought about by polarized wave fluctuation is increased due to the oneor more optical fibers comprising a plurality of conductors.
 18. Theoptical fiber type flat shaped body sensor according to claim 13,wherein changes in form of the optical fiber type flat shaped bodysensor reflected as the shape chance in form of one or more of theoptical fibers generates a fluctuation in polarized light propagated inthe one or more optical fibers, wherein sensor sensitivity brought aboutby polarized wave fluctuation is increased due to a reflection mirrorplaced on one side of the one or more optical fibers so that lightsignals are transmitted in the one or more optical fibers withto-and-from movements.
 19. The optical fiber type flat shaped bodysensor according to claim 13, wherein the optical fiber type flat shapedbody sensor is processed to make a cover for a Futon-bed, a quilt cover,a mat, or a sofa.
 20. The optical fiber type flat shaped body sensoraccording to claim 19, wherein the sensor is provided with a watertightvinyl cover.
 21. A garment styled optical fiber type flat shaped bodysensor comprising: a flat shaped body, wherein the flat shaped body is agarment to be worn by a human being to be monitored; and one or moreoptical fibers affixed to and running throughout the flat shaped body sothat shape changes of a part of the flat shaped body are reflected as ashape change in form of one or more of the optical fibers, whereinchanges in form of a part of the human body of the human being monitoredare reflected as changes in form of one or more of the optical fibers,wherein the one or more optical fibers are sewed up in, or affixed to,the garment that is disposed on the body or the human being while in bedso that the human being is monitored for activity conditions.
 22. Ahuman body fitted optical fiber type flat shaped body sensor,comprising: a flat shaped body, wherein the flat shaped body is a humanbody fitted pad in the shape of a stomach band, a bandage, or a sheet;and an optical fiber affixed to and running throughout the flat shapedbody so that shape changes or a part of the flat shaped body arereflected as a shape change in form of the optical fiber, whereinchanges in form of any part of the human body fitted to the human bodyfitted pad are reflected as changes in form of the optical fiber,wherein the optical fiber is sewed up in, or affixed to, the human bodyfitted pad.
 23. A method as recited by claim 10, wherein the specificwavelength is reflected by optical fiber diffraction.
 24. The garmentstyled optical fiber type flat shaped body sensor according to claim 21,wherein the flat shaped body is a garment selected from the groupconsisting of pajamas, night wear, and a patient dress.
 25. The garmentstyled optical fiber type flat shaped body sensor according to claim 21,wherein the sensor operates to monitor the human being during a medicaltest.